Footwear having an articulating heel portion

Abstract

An athletic shoe with an articulating heel which incorporates a plurality of linkage mechanisms that control heel dynamics. The linkage mechanisms couple a lower heel plate to a spaced apart upper heel plate. A resilient element is located between the upper heel plate and lower heel plate to dampen impact forces and resiliently maintain spacing between the upper and lower heel plates. The linkage mechanisms may be suitably configured alloy bars coupled to the upper and lower plates that constrain the upper and lower plates against motion along a heel transverse axis. Other embodiments of the linkage mechanisms include unitarily constructed panels having flexure joints. During running, the lower heel plate, or an outsole attached to the lower heel plate, will contact and frictionally engage the ground surface while the upper heel plate and footwear will continue forward as the heel articulates about the linkage mechanisms. The impact force will move the upper plate downward compressing the resilient element and the upper heel plate will move closer to, and forward of, the lower heel plate providing heel travel that attenuates the impact forces. The linkage mechanisms constrain the relative motion of the upper heel plate and the lower heel plate against motion transverse of the heel thus providing heel control. The heel dynamics can be further controlled by controlling the orientation of the heel relative to the footwear.

I claim: 
     
       1. Footwear, comprising: (a) an elongate upper having a forwardly located toe portion;   (b) a forefoot sole coupled to the upper proximate the toe portion, the forefoot sole having a lowermost outsole portion;   (c) a heel coupled to the upper and having a lowermost outsole portion, the heel being separated from the forefoot sole by a discontinuity in the outsole portions, the heel further including: (i) a first substantially rigid plate;   (ii) a second substantially rigid plate; and   (iii) a linkage mechanism that is coupled to the first plate and defining a first flexure axis proximate the first plate, and the linkage mechanism is coupled to the second plate and defining a second flexure axis proximate the second plate, wherein the first flexure axis is located forwardly of the second flexure axis so that ambulation impact forces on the heel causes the heel to flex at the flexure axes and move the second plate away from the forefoot sole.     
     
     
       2. The footwear of claim 1 further comprising a second linkage mechanism that is coupled to the first and second plates and that defines a third flexure axis proximate the first plate and a fourth flexure axis proximate the second plate, wherein the third flexure axis is located forwardly of the fourth flexure axis. 
     
     
       3. The footwear of claim 2 further comprising a third linkage mechanism coupled to the first and second plates that defines a fifth flexure axis proximate the first plate and a sixth flexure axis proximate the second plate, and wherein the fifth flexure axis is located forwardly of the sixth flexure axis. 
     
     
       4. The footwear of claim 1, wherein the first linkage mechanism is a configured rigid bar. 
     
     
       5. The footwear of claim 1, wherein the first linage mechanism is a planar panel. 
     
     
       6. The footwear of claim 1, wherein the first linkage mechanism is a panel extending substantially transversely across the heel and the panel is of unitary construction with the first and second plates. 
     
     
       7. The footwear of claim 1, wherein the first linkage mechanism is a panel having a thickness, and the first flexure axis is located along a portion of the panel that is least thick. 
     
     
       8. The footwear of claim 1, wherein the first and second plates include a leading margin and a trailing margin, the leading margin being forward of the trailing margin, and wherein the first flexure axis is located rearward of the first plate leading margin and the second flexure axis is located forward of the second plate trailing margin. 
     
     
       9. The footwear of claim 1, further comprising a resilient element located between the first and second plates. 
     
     
       10. An improved heel for footwear, the footwear having an elongate sole coupled to an upper, the sole having a forefoot portion and the improved heel, and the forefoot portion and heel including a ground contact portion located along a lower surface of the forefoot portion and the heel, the ground contact portion of the heel being separated from the ground contact portion of the forefoot portion by a lower surface discontinuity, the improvement comprising the heel having a first substantially rigid plate that is coupled to the upper, a second substantially rigid plate and linkage means that couple the second plate to the first plate such that ambulation forces move the second plate away from the forefoot portion, thereby attenuating horizontal and vertical impact forces. 
     
     
       11. The improved heel of claim 10, further comprising a resilient element located between the first and second plates. 
     
     
       12. The improved heel of claim 10, wherein the linkage means is of unitary construction with the first and second plates. 
     
     
       13. The improved heel of claim 10, the improvement further comprising a third substantially rigid plate and second linkage means that couple the third plate to the first plate such that ambulation forces move the third plate away from the forefoot portion and the third plate moves independently of the second plate. 
     
     
       14. Footwear having an upper coupled to an elongate sole, the sole including a forwardly located forefoot portion and a rearwardly located heel, the heel comprising: (a) an upper plate coupled to the footwear upper;   (b) a first linkage mechanism that is pivotally coupled to the first plate along a first pivot axis; and   (c) a lower plate pivotally coupled to the first linkage mechanism along a second pivot axis, the lower plate being spaced apart from the upper plate by the first linkage mechanism;   (d) wherein the lower plate is separated from the forefoot portion so that the lower plate can move independently of the forefoot portion, and the first pivot axis is located forwardly of the second pivot axis and the linkage mechanism is substantially rigid so that impact ambulation forces cause the second plate to pivot about the second pivot axis and the linkage mechanism to pivot about the first pivot axis so that ambulation forces move the second plate rearward and toward the first plate.   
     
     
       15. The footwear of claim 14, wherein the upper plate, lower plate, and first linkage mechanism are substantially rigid so that substantially all heel deformation occurs at the first and second pivot axes. 
     
     
       16. The footwear of claim 14, further comprising a second linkage mechanism that is pivotally coupled to the upper plate along a third pivot axis and is coupled to the lower plate along a fourth pivot axis, the third pivot axis being located forward of the fourth pivot axis so that ambulation forces move the second plate rearward and toward the first plate. 
     
     
       17. The footwear of claim 16, further comprising a third linkage mechanism that is pivotally coupled to the upper plate along a fifth pivot axis and is coupled to the lower plate along a sixth pivot axis, the fifth pivot axis being located forward of the sixth pivot axis, so that ambulation forces move the second plate rearward and toward the first plate. 
     
     
       18. The footwear of claim 14, wherein the upper plate is a first length along the longitudinal direction and the lower plate is a second length along the longitudinal direction, and a distance from the first pivot axis to the second pivot axis is a third distance, and the third distance is less than the first and second distances. 
     
     
       19. The footwear of claim 14, wherein the upper and lower plates include respective leading margins and trailing margins, the leading margins being forward of the trailing margins, and wherein the first pivot axis is located rearward of the upper plate leading margin and the second pivot axis is located forward of the lower plate trailing margin. 
     
     
       20. The footwear of claim 14, wherein the first linkage mechanism is a panel having upper and lower margins that couple to the upper and lower plates respectively, wherein the first and second pivot axes are located along portions of the panel that are thinner than other portions of the panel so that heel deformation due to ambulation forces occurs along the first and second pivot axes. 
     
     
       21. The footwear of claim 14, further comprising a second linkage mechanism coupled to the upper plate along a third pivot axis, and a lateral lower plate coupled to the second linkage mechanism along a fourth pivot axis, wherein the lateral lower plate can move independently of the lower plate and the lateral lower plate is substantially co-planar with the lower plate. 
     
     
       22. The footwear of claim 14, further comprising a resilient member located between the upper and lower plates that urges the upper and lower plates apart.